A rotatably supported sole plate of the above-mentioned type is described for example in German OS No. 2 324 078. In this known construction, the sole plate consists of a base plate on the ski and a plate on the boot side. The space between the plates is protected against external influences by an expandable sleeve. The connection between the two plates is created by a bearing, the vertical pivot axis of which extends through the shin-bone axis and the horizontal pivot axis of which extends transversely with respect to the longitudinal axis of the ski in a plane of the vertical axis. The vertical support is constructed as a ball bearing for reducing friction, while the horizontal support consists of a sliding bearing made of bolts and tetrapolyethylene fluoride sleeves.
The foregoing described construction of the known apparatus permits at the same time to recognize the first disadvantage of this solution, namely, the use of many structural parts and the plate also has to have a special design. The use of many structural parts is not only expensive, also the number of tolerance errors increase and the frictional forces which are to be overcome increase. A further disadvantage consists in the structural parts which determine the position of the vertical pivotal support part not permitting any play for receiving of compression forces, which are created by a bending of the ski, for example during travel over a depression. Furthermore it is absolutely necessary that the plate be permitted to pivot about an additional horizontal axis.
It is also known according to Austrian Pat. No. 330 632, to use one single pin or pivotal support part which permits the sole plate to both be pivoted through a limited range in the horizontal and also in the vertical plane, before a release operation takes place. The pivotal support part serves substantially for centering and positioning of the sole plate.
From Austrian Pat. No. 299 030 it is already known to compensate for the bending of the ski by rigidly connecting the sole plate to the ski through a single fastening point. This construction, however, does not permit a pivoting of the sole plate with respect to the ski, so that a spring-loaded locking mechanism cannot be used, which could control the release operations during a twisting fall and partly during a fall wherein simultaneous upward and sideward forces are applied to the binding, as this is for example possible in the aforementioned construction according to Austrian Pat. No. 330 632 and also is to be realized in the case of the subject matter of the invention. For a similar reason, it is also not possible to use the solution according to Austrian Pat. No. 302 130, in which the sole plate is held between two spaced bearing points from the upper side of the ski.
In order to be complete, reference is also made to Austrian Pat. No. 326 015, in which a sole plate is pivotally supported about a pivotal support part and rotatably with respect to a spring-loading locking mechanism in the downhill skiing position. This known solution does not exceed the state of the art which is described in Austrian Pat. No. 330 632 and is already discussed above.
Finally it is also mentioned that various plate mountings made of a relatively thin sheet metal material are known on the market, which have grooves therein, which facilitate an adjustment of these plates to bent skis. Since these plates are constructed necessarily thin, the individual parts are moved into one another, which results in an undesired accumulation of material and results in a constant change of the shape of the plates. Therefore, such a construction could not be successful on the market. Also an attempt was made to construct the plate which is supported on a ski-fixed part with two slots which are arranged substantially transversely with respect to the longitudinal axis of the ski and are each arranged spaced from the pivotal support part, in order to form for the accumulated material nominal receiving points. This construction again has a disadvantage namely the bent areas are created automatically in the slot areas where the material thickness is the least with reference ot the width of the plate and thus breakage of the plate can easily occur. This in particular because the tapered points serve as rests for the entire weight of the skier, since the ski supports the plate along these tapered portions. Similar situations also exist when the grooves are provided extending inwardly from the two sides and the connection is formed by connecting pieces which exist centrally with respect to the longitudinal axis of the ski.
The objects of the invention are to avoid the aforementioned problems and further disadvantages of the known constructions and to provide a sole plate of the above-mentioned type as insensitive as possible also with respect to a bending of the ski. Since furthermore each screw hole in a ski weakens the ski, it is possible to secure the sole plate or its two holding parts to the upper side of the ski with as few screws as possible.
The set objects are inventively attained by the pivot part and the two ski-fixed holding parts of the sole plate being screwed to the ski each with only one screw arranged on longitudinal axis of the ski, and the individual holding parts are each fixedly connected to one centering plate, which centering plates permit a reciprocal shifting upon a bending of the ski by the provision of one elongated hole in each centering plate and which is associated with the pivot part and forms together with the pivot part an enlarged head received in a blind hole of the sole plate, which opens upwardly and limits the vertical movement of the ski relative to the sole plate.
The two-part construction of the centering mechanism enables a deformation-free compensation for a change in length of the ski occurring during a bending thereof. The pivotal support part and the blind hole are thereby inventively constructed so that they permit the sole plate to be positioned during bending of the ski on a chord with respect to an arc defined by the ski.